In the cooling of houses and commercial buildings, refrigeration equipment operating on a well known cycle is customarily used. The cycle of operation is fairly well spelled out by describing the equipment associated with the apparatus. Refrigerant flows in a closed, endless loop. The flow is initiated by a compressor which is a large pump. The compressor pumps the refrigerant which flows through a cooling coil to surrender heat and, thereby, drop the temperature. At this point, the refrigerant becomes a cooled liquid. The refrigerant flows through an expansion valve. Upon expansion to a gas, it tends to cool. It flows, while cooling, through another heat exchanger which is often called an evaporator. External to the system, a fan driven by a motor blows air over the evaporator coil to thereby cool the air. The endless loop continues from the evaporator coil to the compressor pump.
The present invention is apparatus adapted to be substituted in the refrigeration equipment described in very broad terms above. While the remaining components of the refrigeration equipment remain unaltered and are well known, this invention is a modification whereby power reductions in operation can be achieved. This invention yields savings in size or scale and may, in some instances, reduce cost of operation.
A large portion of the power required for refrigeration equipment is required by the compressor motor. By and large, it is an electric motor driving a gas compressor or pump which picks up high temperature, low density refrigerant gas. The gas is compressed to a high pressure and temperature. Thereafter, it passes through a heat exchanger or condenser. By giving up heat at the condenser, the temperature of the highly compressed vapors is dropped sufficient to bring about a change in phase to a liquid. The liquid is then transferred through the endless cycle. The compressor must work with vapors, not incompressible liquid, and it is in this area that substantial amounts of power are used, and, yet, the power is converted only into heat by attempting to raise the pressure of the highly compressible gas.
The present invention contemplates a reduction in electric power consumption by modifying the cycle through the use of a combined condenser, support structure and a liquid refrigerant pump. A tremendous gain can often be achieved by placing the liquid pump downhole so that it is submerged in a sump and surrounded by liquid refrigerant. This provides it with an in-flow of liquid refrigerant, and it, therefore, does not operate inefficiently by compressing a highly compressible gas. Rather, the pump must impart pressure to an in-flow of incompressible liquid. A surface-located compressor (seen in one embodiment) works at greatly reduced discharge pressure as a result of efficiency gained on subterranean heat transfer.
The present invention is particularly able to save power in operation in comparison with known cooling towers. As an example, a cooling tower using air as a medium is dependent on the temperature of the surrounding air. At the time when the maximum load is imposed on an air cooled system, the temperature differential between the cooling medium (the surrounding air) and the refrigerant is minimal. The same is practically true for a cooling tower using water. Many cooling towers utilize water. The water assumes a temperature which is, in large part, dependent on the air temperature. While the air temperature may fluctuate hourly, the water in the cooling tower system will settle on a norm which is somewhat dependent on the long time average of the surrounding air temperature. Thus, the compressor discharge pressure is relatively high and, therefore, requires increased pressure.
Through the use of the present invention, downhole artesian formations are utilized as a heat sink. They normally operate at a fairly well established temperature. It is normally rather stable. This permits the design of the system with maximum temperature differential between the temperature of the refrigerant (on the heated side of the evaporator) and the cooling medium, the artesian water. More importantly, water temperatures in this arrangement typically run around 10.degree. to 15.degree. C. For instance, in an artesian well of about one hundred meters in depth, several artesian formations may be penetrated. Each artesian formation will have a normal operating temperature that is almost invariant, perhaps varying no more than one or two degrees Centigrade between winter and summer. This, of course, depends on a multitude of local factors, including the rate of introduction of water to the formation, rate of withdrawal, proximity to the surface and so on. As will be appreciated, the present invention is, thus, a marked improvement over devices known heretofore. In particular, it is an improvement by providing reduced power consumption, or, restated, more cooling power for a given rate of power consumption. This invention also reduces surface equipment installations. Cooling towers are constructed on the surface behind or on top of buildings. Through the advent of this invention, they can be located substantially out of sight, literally having no more than a visible wellhead. They enable joint use of an artesian well, namely, for the purpose of pumping water for water consumption and also utilization of the well as a cooling tower.